US2598548A

US2598548A - Meat processing machine

Info

Publication number: US2598548A
Application number: US37776A
Authority: US
Inventors: Aldrich L Jackson
Original assignee: HOBART FED ENGINEERING CORP
Current assignee: HOBART FED ENGINEERING CORP; HOBART-FEDERAL ENGINEERING Corp
Priority date: 1948-07-09
Filing date: 1948-07-09
Publication date: 1952-05-27
Anticipated expiration: 1969-05-27

Description

May 27, 1952 Filed July 9, 1948 A. JACKSON MEAT PROCESSING MACHINE 6 Sheets-Sheet 1 FIG.

FIG. 2.

INVENTOR.

, ALDRICH L. JACKSON May 27, 1952' A. JACKSON 2,598,548

MEAT PROCESSING MACHINE Filed July 9, 1948 6 Sheets-Sheet 2 INVENTOR ALDRICH L. JACKSON BY w ' ATTORNEY I A. L. JACKSON MEAT PROCESSING MACHINE May 27, 1952 Filed July 9, 1948 6 Sheets-Sheet 3 INVENTOR. ALDRICH JACKSON y 27, 1952 A. L. JACKSON 2,598,548

MEAT PROCESSING means 1 Filed July 9, 1948 6 Sheets-Sheet 4 1 F|G, 8, 43 44 50 I, B

INVENTOIL' ALDRICH L. JACKSON ATTORNEY y 27, 1952 A. L. JACKSON MEAT PROCESSING MACHINE 6 Sheets-Sheet 5 Filed July 9, 1948 INVENTOR ALDRICH L. JACKSON ATTO'NEY y 27, 1952 A. L. JACKSON 2,598,548

MEAT PROCESSING MACHINE Filed July 9, 1948 6 Sheets-Sheet 6 INVENTOR. ALDRICH L. JACKSON FIG.

Patented May 27, 1952 UNITED STATE OFFICE MEAT- PRQGESSING MACHINE Aldrich L, Jachson;.Minneapolis, Minn, assigncr to Hobart-Federal Engineering Corporation, Minneapolis, Minm, a corporation of Minnesota Application July 9, 1948,.Ser-ial-No; 37,776

3 Claims. (Cl. 17f--26)- My invention relates to a meat-tenderizing' inachine wherein a tenderizing unit is provided through which the meat is adapted to be passed.

A primary feature resides in providing means for receiving the tenderizing unit which includes a casing adapted to house an electric motor and a transmission unit operated by the motor, the motor and transmission unit being concealedwithin the casing. The casing is adapted to receive the tenderizing unit into operating position tocontact the transmission unitbyholding the unit with one end restingon a receiving shelf in the casing and rocking the other end into position inthe casing; where a keystone.- like shoulder meansreceivesthe end of the unit as it is rocked into operating position. Thus the tenderizing unit is locked in place. The tenderizing unit can be removed in the; same manner by a rotating movement which lifts one end of the unit out of the keystone-shaped recess and as this end of the'unitis raised theother end of the unit is released-from the driving. transmission.- It is an important feature to'provide a means for supporting the tenderizing unit so that it-can be engaged by the handof theoperator to lift it out of operating position bya rotating movement or it can be re-inserted intooper-ative position by a rotating. movement. Thus I provide an easy means of handling.- the tenderizing unit so that the free end of the same can be lifted from a locking recess (which is keyshaped) and through this lifting movementof the fr-lee end ofthe unit,, the other end of the unit'is'disengagedfrom'the keyclutch ofthe transmission unit,-

It is also a-featu-reto provide atenderi'zing and processing unit for meat,.which iscomposed offltwo sections, each of which is provided with a sh'a'ft upon wh'icliare mounted a series oftend nzingknives held s aced apart, the ,li'nive of the-respective e tions overla ing and fitting between each other when the sections are assemblccliin a unit. A feature" o'fthe tenderizi rjrg unit which is of' primary importance resides in a means of hinging the "sections" of the unit together on one end one key which permits the sectionsto be rotated on the key toward and away from each oth'e'rfin separating the sections entirely" from eachother' and which holds the sectionsinline'with eachother on one-end and; leaves the ether end of the sections free to be separ''a'ted or to be moved adjacent each other against bearingfaces ofthe' frames of the sec-- tion's whichhold the same line whenthe sec-' tio'n's are held as a unit w-ithin the supporting casingi A furtherfeature resides in means for supporting one'section in the supporting casing s o'that it can be operated by .the power meansan'd'per mit the operatorto sharpen the blades; Either section of the unit can be held separately'inthe' recess of the supporting casing or the sections may be held as a unit when in processing position in the casing. The separable sections of the tenderizing unit permit each section to be there oughly cleansed when separated fromthe' other section in addition to the advantage of operating either one of the sections individually in" the casing as just described.

A further important feature of my tenderizing andprocessi'ng machine resides in the casing; which is formed with a central recesshajving. a bottom forwardly inclined wa1l,.the ends oi'the' recess joining this wall to form a smooth closed casing at each end of the recess which provides the recess with a smooth surface throughout its entire form which can be readily cleansed when the tenderizing unit is removed from the casing,

I also provide a hinged cover for closingthis central recess and forming a protective means over the top and front of the tenderizing. unit when this cover is closed. However, the forwardly inclined wall is spaced from the lower free end of the cover to provide a'chute-likeopen'ing out ofwhich the tenderized meat drops when it leaves the tenderizing unit. The tenderizing unit is formed with guiding means in the form of strippers. The cover is formed with a longitudinal slot, and depending from the same within the cover and formed integral therewith is a flange which forms a chute-like opening extending toward the tenderizing unit, which guides the meat to the tenderizing unit. 7 V

A feature of the tenderizing unit resides a pair of handles, one of which is formed on the frame of each section of the unit, and these meat passes through the tenderizing unit: thefloating stripper members which have ends. projecting beyond the tenderizer blades form guides to direct the processed meat onto the in]- clined shelf which discharges the same out ofthe machine.

It is also a feature" to provide a unit frame" for supporting theelectric motor and power J transmission unit within the casing. This frame .In addition, these handles 3 is attached to the casing below the recess by bolts which also support the hinge of the cover.

A further feature resides in providing a casing formed of a' single piece which conceals the electric motor and transmission unit and wherein the central recess is formed to receive the tenderizing unit with shoulders at each end of the recess upon which the ends of the tenderizing unit rest. One of the shoulders receives the end of the tenderizing unit first and the other of the shoulders receives the free end of the tenderizing unit as it is rocked into operative position in the casing. In forming the casing of a single piece of material I have provided a very desirable support for the tenderizing unit, which permits the unit to be removed by lifting the free end of the same and rotating it out of engagement with the clutches of the power unit. Then the recess may be wiped clean and thereby a sanitary support and casing for my machine is provided which is highly desirable in a machine of this character used for processing or tenderizing meat, where. one of the first essentials is cleanliness. a a

The simple form of my casing with the central recess. for receiving the tenderizing unit permits the processing or tenderizing unit to be rotated into place ready for operation. The unit may be lifted out of operating position by raising the free end thereof which is opposite the driving clutches and rotating the unit up out of the machine.

The central recess formed in the casing has formed integrally therewith in the end walls of the recess the guiding shoulders for the ends of the processing unit. This is important in forming. a simplified construction which provides smooth clean surfaces without any cracks or joints whichcould not be easily cleaned. Normally the one-piece casing is white enamelled like other fixtures in a butcher shop. Thus the entire outer surface, including the recess in the casing and the shoulders at the ends of the same, is smooth and finished with an enamelled surface which is sanitary and may be easily cleansed when the unit is removed.

Thefeatures and objects of this invention will be more clearly and fully hereinafter defined.

In the drawings forming a part of this specification: Y

Figure 1 is a front view of my meat tenderizing machine showing the cover elevated and the tenderi'zing unit in position to be inserted into operative position in the casing.

Figure 2 is an end view of my tenderizing machine showing the cover closed.

Figure 3 is an'enlarged section longitudinally through the casing showing the tenderizing unit removed, the cover of the casing closed, and showing the electric motor with its enclosed chain of driving gears positioned as a unit within the casing.

Figure 4 is an enlarged sectional detail showing the clutch engaging one end of the shafts which support the'tenderizing rollers.

Figure 5 is a perspective detail of the end of the shaft which carries the key portions which are adapted to fit in the clutch of the motor driving unit.

Figure 6 is an enlarged sectional detail showing one section of the tenderizing unit in place supported in the casing of the machine and showing the cover in closed position. V

Figure"? is a similar section to Figure 6 looking in the opposite directionand showing one of the sections of the tenderizing unit supported in position within the casing.

Figure 8 is a plan view looking down on the sections of the tenderizing unit which are spaced apart from each other to illustrate the manner in which the sections are freely separable one from the other by simply moving the sections away from each other.

Figure 9 illustrates an end view of the tender izing unit showing the sections together and looking at the ends of the shafts of the unit which carry the driving keys which engage the clutch of the driving mechanism when the unit is placed in the machine.

Figure 10 is an end view of the tenderizing unit showing the sections together and held by a floating key and looking in the opposite direction to that shown in Figure 9.

Figure 11 is an enlarged cross section on the line |lll of Figure 1, through the tenderizing unit only, when the sections thereof are held engaging each other and showing the position of the floating stripper members in relation to the hubs of the tenderizing rollers.

Figure 12 is a perspective view of the casing of my machine showing the cover thereof removed and illustrating the central recess with the forwardly inclined bottom wall and showing one end Wall with the recess for receiving the free end of the tenderizing unit.

Figure 13 is a perspective view looking toward the front of the casing, with the cover removed and looking toward the opposite end to that shown in Figure 12, to show the recess and shelf for receiving the clutch ends of the shafts of the processing unit.

Figure 14 is a section through the tenderizing unit similar to Figure 11, showing the cutter blades in dotted outline and illustrating the floating strippers in full lines with the bar which connects the end plates in section.

Figure 15 illustrates a perspective view of each of the stripper comb units as they appear removed Figure 18 is an enlarged section on the line I8|8 of Figure 16.

My meat tenderizing machine A is composed of an outer housing l0 constructed of metallic or nonmetallic material. A recess II is formed in the outer housing l0 adapted to receive the tenderizing unit B which will be fully hereinafter defined. The unit receiving recess I I has a shelf I2 formed longitudinally of the rear portion thereof to which is hinged the cover portion l3 which is virtually flush with the outer casing and completely covers the tenderizing unit B when the same is closed for operation of the machine A. The cover I3 is formed with a meat receiving slot [3' on the top portion thereof.

I provide a one-piece integral frame [4 which is secured to the under side of the shelf l2. The frame I4 is composed of the vertical members I5 and I6 which are joined at the top by a horizontal member M which extends under the shelf l2 .and is secured thereto by the bolts 12. The central brace member I! and the bottom longitudinal member I8 connect the members l5 and I6. The bottom surfaces of the members I5 and iii are positioned slightly above the bottom edges of the outer cover or casing I 0. The vertical or aeeew re upright member [:65 supports'the gear housing I9; The g'ear housing unit I9 contains a series of gears whichare" driven by the'motor 'through thefiexible coupling .211 The series ofgears with In the gear housing I9 are adaptedto drive the clutches or couplers: 22 which are" cup like in shape and have engaging. teeth 23'formed'on'the rims ithereof; The recess IIformed in'the'outer casing i is-finished off in the upper portion thereoii by the'end wear or

striker metal plates

24 and 25 which are secured by the bo1ts26- and 21 respectively-

The'bolts

26 and 21 are secured intotthe' upright end walls 24" and 25' respectively. .The' plate 24. is' formed withthe inclined shoulders and'29.- The plate 25*is formed with 'I-he clutches or couplers: 22 are recessed inthe lowenthickened portion of the plate25 and vir tually'flushwith the surface thereof. tudinal Wall portion 34 inclines from the shelf portion I2- downwardly to an a'rcuated portion beneath the unit B and then slants downwardly toward thefront of the casing? I0 to forma meat chute surface 35', allfof which ispart of the bot-- tom ofthe recess I I hereinbefore mentioned formed in the-outer casing III-J The b'oltsIZ' support; the lower plate 36 of. the hinge '31; The upper' plate 380i. said hinge secured bythe bolts 39 to the cover I3. The front free end 400i the cover l3 may be engaged to lift theicoveri by inserting the hand in the lower end ofthe'recess ll adjacent the wall 35 of the bottom; of the recess; When the cover I3 is raised into the position illustrated inFigurel, the sectional tenderizing: unit B is exposed. This permitsi the operator to engage the tenderizing unit to lift it from the-recess II or re-insert' it therein.

The sectional tenderizing unit B is illustrated in Figure 1 as'it would appear when it is being in serted in the recess I I or removed therefrom;

The sectional tenderizing unit B is made in-two sections, 4I' and 42, illustrated-in plan view in Figure 8, and they are separated from each other to show the manner in which the sections m'ay be separated-when the unit B is removed from the recess II.

Each section 4| and 42 is provided with" a tenderizing roller 43 which is madelup ofa series of draw cutting knife toothed'discs 4,4: The discs 4tv are formed with teeth as illustrated-in-Figures 6' and' 7, which are formed with sharp bevelled ends 45'. The cutter discs 44 0f there-- spective tenderizing rollers of each section 41' and 42-rotate toward each other in operation, and

the sharp knife-like ends'45' of the teeth of-the discs Mare-adapted to make draw cuts in thebody-fof the meat as it is drawn by the processing rollers'43 through the tenderizing unit B. The meat isadapted to be dropped by gravity through the slot I3 in the cover I3.- I-Iand rails'46 which are formed on the top of the frame portions of each of the sections 4 I and 42 permit the operator toengage the unit B to lift it from the recess-all or to insert it-thereinas illustrated :in Figure 1;

The sections and 42 are adapted'to beheld; in alignment with each other by the floating key 41 which is secured to the section 42 and is-"adapt ed to fit-into the recess 48' formed in" the: sec-- tion receive the outer end of thekeyl'l'.

A longi- I The outer end of the key 4'1 is arcuated and the recess 48' is similarlylshaped to freely The end frame portions of: the sections 4 I1: and

42' have a: meeting? or; bearing surface?- 4 9 which" virtually centrally divides the-sections and which provides a bearing surfaceso' that: the-frames of the sections 4| and 42 may bear against; each other as illustrated in Figures 9, l0 and' 11 when the" unit Bis assembled;

The rollers 43 are made up of a series of toothed:

disc; cutter blades 44 which blades are spaced:

apart by the hub washers 50 which. rigidlyclampi the cutter blades 44 on the shaft 51 of each of' the sections: 4 I" and 42; The shafts 511 are mounted in'the-end plates of: the frames or the respective sections 41' and- 42,.an'dl at one end theshaft's 5I' project through'the plate and are fo'rmedwith a roundedfiend portion 52. A pair of keys53 pro jecturom the rounded ends 52 of the shafts. These key portions 53fareadapted to engage the which engage the inclined surfaces 28' and-= 29 when theunit B i's'ihsertedinto the'rec'e'ss I I'-.-

A central lug is formed projecting-1mm the shelf 33 and this mg is" adapted to" fit into the recess STformed-in the-ends of the'frames'otthesection's 4I- and 42 which are pr'ovidedwiththe inclined-surfaces -'54 and 55' (as-'illustrated 'in Fi ure 10).. The lug 55fis'provided tokeepthe espectivesections suchas-4l and 42 positione'd in dividually' in the'recess' I I (as illustrated in Fig ur'es 6 and '7); It is desirable that' tli'e sectioris' 4| and'42 be individually placed in the" recess- I I motor'20 may be operated't'o rotate eithero-f "the" section's 4'I or 42- individually when they" are-pp: sition'e'd as illustrated in Figures 6 or 7.

The-hand rails 45- act;as"a-cliute to g'uide 'the meat" passing throughthe opening I3 intoen:

gagerner'it with'the'cutterdiscs 44; These hand:

rails" are rormedwith 1ower guaru wa1ls which preventthe operators fingers from com ing in contact with the blades 44 duringthe re I mov'al or insertion of the tenderizing'un-it Theu nit B -is' formed With a -hcrizonta11y rojectingshoulder' 6 I whichis adapted to engage the inclined surfaces 30 and 3 I and come-"to res't upon-the self 32to properly place the unit B in workingposition in the recess I I. The lower edge 62 of theframe sections ll and 42--'which-a;re

iorn ied with the inclined surfacesi t'and 55 (as illustrated-in Figure 10) is adapted to rest upon: the? horizontal shelf 33' when the unit-B'is-in workirig'pos'ition in the recess I I Each'of the sections M and 42 is'formecl 'withfloating stripper units C. The units C are piv-'-- oted to therespective sections M and 42 at I53;

These-units C are formedwith lower barportions 64 which extend between the ended the frames of the sections M and 42 andwhich support the" hub scraping teeth 6-5 which project betw'eenthe blades 44 and: engage'the hubsiE'B'tokeep the hubs clean and-at the same time clean the' sides of the bladesz The'fioating stripper units Galso:

act to guide'zthemeat from the pI'OCGSSIIIgFI'OH-'-' ers 43" and as" the meat passes between the strip?" per-C it is deposited on the inclined surface35 as" it is" discharged from thetenderizi-ng unit B;

.The bars 46 are formed with longitudinal ribs 46' to facilitate the'gripping of the unit Bin removing it or inserting it into the recess II.

It is of primary importance in my invention to provide a tenderizing unit of a simple construction wherein the casing entirely houses the power unit made up of the motor and the transmission gears |9 withthe clutches 22.. The cover |3 closes the top of the recess II to protect the operator from the tenderizing unit B. Different kinds ofmeat may be stitched together by dropping the same through the slot I3 which is guided by the rails into the processing rollers 43 which tenderize the meat and stitch it together. so that steaks maybe made by stitching beef with pork, and steaks may be made out of the meat of fowl such as turkeys, chickens and similar fowl, which steaks may be readily combined with different meats by stitching the meat together and at the same. time draw cutting it by the teeth of the blades 44 and thereby tenderizing the meat without crushing it.

A further important feature of my invention resides. in the sectional unit B, whereinthe sections 4| and 42 may be quickly and easily separated from each other for cleansing when the unit B is removed from the recess H, and permitting the respective sections to be sharpened individually while the motor is operating.

A further feature of primary importance resides in the manner in which the unit B is automatically locked in the recess II by engaging with the

inclined shoulders

28 and 29 which engage the surfaces 54 and respectively and by the engagement of the transverse lug Bl which engages the shoulders 30 and 3| to securely position the sections 4| and 42 together while in the of joining the free separable sections 4| and 42 is unique in that it holds the sections together as a unitduring their operation of tenderizing meat or stitching the same together, and yet the operator may lift the cover l3, engage the rails 46 and remove the sectional unit B from the recess and the clutches 22, and immediately the sections, 4| and 42 may be separated (as illustrated in Figure 8), which permits the free access for cleaning of the respective sections or the replacement thereof by other sections whenever it is desired.

The simplicity of my tenderizing unit with the novel manner in which I fully enclose the operating-parts and protect the operator from the blades of the unit B, and yet providing a receiving recess 3| together with a discharging surface 35, accomplishes a result which is very desirable in a machine of this character. It will be apparent that when the unit B is removed from the recess H (as illustrated in Figure 3), the entire recess is accessible for cleaning, and there are no crevices which cannot be readily cleansed when desired. At the same time the power unit including the motor 2|) is enclosed and protected.

It is very desirable that a meat tenderizer or processing machine of this character be made absolutely sanitary for complete cleansing and inspection at all times.

A further feature of primary importance in my tenderizing unit is the unique manner in which I support the power unit with the motor 20 in the casing Ill. The one-piece metal frame I4 is hungfrom the self |2 of the casing by the same bolts I2 which secure the hinge 31 for the cover |3. Thus a simple and very eflicient means of supporting the power unit with the motor 20 and recess H and in operationg position. This means the gear unit I9 is provided. The frame M which is formed in a single unitary part provides a strong means of supporting the power unit in a manner so that the casing entirely encloses and separates the power unit from the recess II which receives the tenderizing unit B. The motor 2|! may be operated by a suitable switch such as D, which may bepositioned as illustrated in Figure l on the front of the casing or in any other suitable position where it is freelyaccessible to the operator. 7

When the unit B is removed, the sections 4| and 42 may: be individually placed under a Water faucet to thoroughly and effectively cleanse the respective sections of the unit. It is also a feature to separate the sections 4| and 42 from each other to make it easier for the operator to handlethe sections when they are removed from the operating position in the recess I.

It will also be apparent that steaks can be made of different kinds of meat suchxas beef,

veal, ham or pork. Turkeyor any other meat. from fowl can be processed into steaks by my machine.

It therefore will be apparent that my machine has a wide range of uses and the processing operation tenderizes the meat without destroying the flavor or crushing the juices from the fibers of the meat. These are important features and uses of my meat processing machine.

In Figures 12 and 13 I have illustrated perspective views of the casing to show the end recesses which receive the tenderizing unit B when it is supported in operative position in the casing. In these figures the unit is removed to more clearly illustrate the formation of the recesses. It will be apparent that the casing is provided with' smooth inner surfaces in'the central recess owing to the integral formation of the casing which is formed. in a singlepiece, and the

back walls

34 and 35 which incline forwardlyare formed integrally with the casing to provide a smooth finished surface which normally' is enamelled with a white smooth surface which can be readily cleaned and kept entirely sanitary at all times. The entire recess H with the end walls are freely accessible for cleaning when the unit B:isremoved from the casing. The blades I2 support the unit frame M as well as the hinge 31, and the unit frame I 4 supports the-electric" end down into the recess and onto the shoulder 33 with the inclined surfaces28 and 29 wedging the ends of the frame of the sections together to hold the same locked in operative position. The free end of the unit B is lifted from the shelf 33 and disengaged from the

sides

28 and 29 as itis lifted from the casing H] of themachine. This provides an extremely simple and yet very effective means of supporting the ten-derizing unit in the casing.

In Figure 14 1 have illustrated a section through the tenderizing unit B with the cutting blades shown in dotted outline and the floating stripper comb units C illustrated in full lines, with the bar 64 thereof in section; V

In Figure 15 I have illustrated both of the floating stripper comb units C removed from the tenderizing unit B.

The comb units C are made up of the series of teeth 65 which scrape the hubs 50 to keep the same clean (as illustrated in Figure 14). The teeth 65 are adapted to project from the bar 64 in each of the comb units C. The lower ends of the fingers 65 are rounded off at 65' which permits the meat passing between the stripper comb units C to readily slide off of the lower free ends of the units C.

The bar 64 connects with the end brackets 64'. The end bracket 64' on one of the comb units C is formed with a convex curved surface 15 while the end bracket 64' on the other unit has a concave surface 16. Above the convex and

concave surfaces

15 and 16 respectively on the end plates 64' a flat bearing surface 11 is formed on each of the end plates 64' so that when the stripper units are in operative position (as illustrated in Figure 14) these flat surfaces 11 bear against each other and thereby hold the stripper comb units C spaced apart with the pointed ends of the teeth 55 bearing against the hubs 50.

The stripper comb units C are preferably formed of die castings, being made in a single integral piece in comb-like form with the end plates 64 pivoted at 63 to the end plates of the sections 4| and 42.

Each comb unit C follows with the respective sections 4| and 42 to which it is attached when the sections are removed from the supporting casing in the central recess thereof, as heretofore set forth.

The bar 64 of the respective comb units C forms the base of the respective teeth 65 of the stripper comb units. The teeth 65 fit between the cutter blades 44.

When the unit B is removed from the supporting casing and the respective sections 4| and 42 of the unit are separated from each other, the stripper comb units C may be rotated on their pivot 63 to swing the comb clear of the teeth to permit cleansing of the tenderizing unit B Whenever it is desired.

The stripper comb unit C has formed on the inner edge of the bar 64, the rounded shoulder segment portions '64" which direct the strippings of meat inwardly toward the meat receiving surface of the comb and also downwardly as the teeth of the blades 44 pass adjacent the portion 64 which is best illustrated in Figure 14. Without the rounded shoulder portions 64", strippings of meat tend to be carried through with the teeth of the blades 44 and clog up between the teeth and the bar 64 necessitating frequent removal of the meat strippings which is the case where the construction of the base bar is angular and not rounded as the 64".

The teeth 65 blend with and are integral with the base bar 64 as at 18 at which point the teeth are rounded as at 19 thereby reducing the contact surface of the teeth with the meat. After the meat has left the cutting blades 44 and is passing out between the lower portions of the stripper comb C, the surface as at 18 form working surfaces over which the meat slides in its downward course between the stripper combs. The teeth 65 have formed on the free ends thereof, the tapered surface 80, the point of which rests on the hubs 50 and efficiently cleans the same.

I claim:

1. A meat tenderizing machine including a casing having a recess therein, power driven means having clutch means thereon in one end of said casing facing said recess, ledges formed in each end of said casing facing said recess and a separable rotary knife type meat tenderizing unit having two sections in said recess, at least one section of said unit having a clutch means at one end complementary to, and in engagement with, the clutch means in said casing, said sections being adapted to be pulled apart from each other when removed from the casing, the ends of said sections opposite said clutch ends having freely removable interfitting hinge means and the clutch ends fitting snugly against each other when in operative position: means for guiding said unit to, and to assist in maintaining it in, said recess; comprising cam shoulders formed in the ends of said casing facing said recess above said ledges and supporting means on each end of said sections resting upon said ledges.

2. The structure of claim 1 wherein the supporting means on the section ends having the clutch means are lugs near the top of the ends and the means on the other ends comprise the bottom of said end portions.

3. The structure of claim 1 including a lug formed on the ledge opposite the end containing the clutch means and an indentation formed in the hinged end of each section, said lug being adapted to engage each of said indentations in such manner that each of the sections may be maintained separately in the casing.

ALDRICH L. JACKSON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,163,123 Huse June 20, 1939 2,360,729 Spang Oct. 17, 1944 2,450,688 Richard Oct. 5, 1948